There is an urgent need for guidelines for monitoring of genetically modified higher plants, GMHP. Biotech crops are now cultivated in large scale in North America and elsewhere. In Europe, new genetically modified (GM) products will probably be placed on the market soon and made available of any negative ef for cultivation in the field. Monitoring and surveillance programs for detection fects to the environment must be designed and ready when these crops are released. This also corre sponds to the current intentions made by the European Commission to include monitoring in current biotechnology regulation. Monitoring of changes in biological systems is different from other types of environmental monitoring, such as monitoring fate of chemical pollutants, by focusing primarily on organism survival and organism interactions instead of physical and chemical parameters. The difficulties involved in monitoring biological systems are great, due to the complex interactions between organisms and the variability in responses. Problems concerning spatial and temporal pa rameter variation increase the difficulties, but may be remedied somewhat by the use of "baselines". These and many other questions are discussed in the present book with the aim of presenting practi cal solutions to the needs of GMHP monitoring. A project was initiated in 1998 to produce a book with guidelines for monitoring and surveillance of GMHP. In two earlier books, compilations of current test methods for risk assessment of GMHP were presented (Kjellsson & Simonsen 1994, Kjellsson et al. 1997).

Forests represent a remnant wilderness of high recreational value in the densely populated industrial societies, a threatened natural resource in some regions of the world and a renewable reservoir of essential raw materials for the wood processing industry. In June 1992 the United Nations Conference on the Environment and Development (UNCED) in Rio de Janeiro initiated a world-wide process of negotiation with the aim of ensuring sustainable management, conservation and development of forest resources. Although there seems to be unanimous support for sustainable development from all quarters, there is no generally accepted set of indicators which allows comparisons to be made between a given situation and a desirable one. In a recent summary paper prepared by the FAO Forestry and Planning Division, Ljungman et al. (1999) find that forest resources continue to diminish, while being called upon to produce a greater range of goods and services and that calls for sustainable forest management will simply go unheeded if the legal, policy and administrative environment do not effectively control undesirable practices. Does the concept of sustainable forest management represent not much more than a magic formula for achieving consensus, a vague idea which makes it difficult to match action to rhetoric? The concept of sustainable forest management is likely to remain an imprecise one, but we can contribute to avoiding management practices that are clearly unsustainable.

This book has been developed as a forest inventory textbook for students and could also serve as a handbook for practical foresters. We have set out to keep the mathematics in the book at a fairly non-technical level, and therefore, although we deal with many issues that include highly sophisticated methodology, we try to present first and foremost the ideas behind them. For foresters who need more details, references are given to more advanced scientific papers and books in the fields of statistics and biometrics. Forest inventory books deal mostly with sampling and measurement issues, as found here in section I, but since forest inventories in many countries involve much more than this, we have also included material on forestry applications. Most applications nowadays involve remote sensing technology of some sort, so that section II deals mostly with the use of remote sensing material for this purpose. Section III deals with national inventories carried out in different parts of world, and section IV is an attempt to outline some future possibilities of forest inventory methodologies. The editors, Annika Kangas Professor of Forest Mensuration and Management, Department of Forest Resource Management, University of Helsinki. Matti Maltamo Professor of Forest Mensuration, Faculty of Forestry, University of Joensuu. ACKNOWLEDGEMENTS

Weeds are variously defined as plants growing where they are not wanted, plants that interfere with human activity. Weeds affect everyone in the world by reducing crop yield and quality, delaying or interfering with harvesting, interfering with animal feeding, reducing animal health, preventing water flow, as plant parasites, etc. It is estimated that those problems cause $ billions worth of crop losses annually and the global cost of controlling weeds also runs into many $ billions every year. Atlas of Weed Mapping presents an introductory overview on the occurrence of the most common weeds of the world. The book notably includes: Description of cropping practices and explanations for the global distribution of weeds Invasive plant mapping Aquatics and wetland plants with histological plant details Theoretical and practical aspects of weed mapping Aspects on the documentation of herbicide resistance Biodiversity, rare weeds and the dominance of the most common weeds Fully illustrated with more than 800 coloured figures and a number of tables, this new characterisation of anthropogenic vegetation will be interesting for readers of a great number of disciplines such as agriculture, botany, ecology, geobotany and plant community research. More than a hundred experts have contributed data to this unique compilation.